Dummkopf

Why is it that when one opens a door of the E350 Coupe, both windows, the door window and the rear side window move ever so slightly? When the door is then closed, the windows go back to their original closed positions.

Thanks, Joe.

steelgrey

Because there are no B pillars. It allows the windows to fit snugly without banging them together or in the case of the front window into the roof molding. It provides for a tight seal and smoother aerodynamics. My only concern is for the longevity of the window motors since they get used everytime the door is opened/closed.

Dummkopf

Got it. Thanks.

BenzMan369

My only concern is for the longevity

You and me both. But it certainly is an effective design for preventing rattles, leaks, etc.....so far.

Especially considering the stiff suspension/ride with 18" wheels and OEM tires.

ronsc1985

The reason they do this is so the doors close smoothly. In a car with no internal leaks, when you attempt to close a door the increased air pressure in the cabin tries to prevent the door from closing completely unless you really slam it. Leaving windows slightly down for a moment allows the interior cabin pressure to equalize to the outside air pressure and thus eliminate a pressure differential across the door. Remrember a door has a lot of area so even a small differential can result in a large force on the door i.e force = the pressure differential in lbs per square inch x the area of the door in square inches.

C6 Corvettes use the same method for the same reason as do some other cars.

As to motor wear/load it is negligible since the windows are moved so little.

mis3

Longevity was my concern as well when I bought my 2004 CLK320 eight years ago. I felt that it was too much going on for a simple task.

Now after 150k miles, they are still working properly.

steelgrey

I'm happy to hear that. The Infiniti G35 Coupes have had the same feature since 2003 on the front windows (no rear windows) and there have been numerous posts about window motors failing. I have a 2003 coupe and have not had a problem but, I only have 21,000 miles on the car.

OBXbeachBUM

My 2002 CLK 320 also has that feature on the windows and it continues to work flawlessly, and well, without any problems whatsoever.

4MaticCoupe

BMW's have been doing this since (at least) the late 90's ... my '98 E36 M3 Coupe had this feature